The result of an approximation by rounding.
The rounded value of a number is an approximate value of this number obtained from its decimal expansion, and reducing the number of significant digits.
Therefore, a rounded number produces a result that is less precise but easier to use in some calculations or estimations.
Example
The number 156 can be rounded to the nearest ten at 160, because 156 is closer to 160 than to 150.
Educational Note
When rounding a number, in a given context or following a calculation, the vocabulary to use can become a source of confusion for students. This table should help clarify this issue by presenting the different terms used.
| Term used | Notation (if it exists) |
Associated function |
Example |
| Value rounded to an order of magnitude | n/a | n/a | The value of 45.09 rounded to the nearest tenth is 45.1. |
| Value rounded down | ⌊x] | Function of the whole part |
The number of teams of 5 players that we can form with 14 available candidates is 2, because 2 is the greatest whole number that is less than or equal to 14 ÷ 5 = 2.8. |
| Value rounded up | ⌊x] | Function of the least whole number that is greater than or equal to | The tickets for a draw are being sold in blocks of 10 tickets so we must buy 5 blocks to accommodate 42 interested people, because 5 is the least whole number that is greater than or equal to 42, since: 42 ÷ 10 = 4.2. |
| Whole part | [x] | Function of the whole part | The whole part of the decimal number 27.686 is 27. |
| Nearest whole value | n/a | n/a | The nearest whole value to 67.408 is 67. The nearest whole value to 67.601 is 68. |